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ColBERTv2

Setting up the ColBERTv2 Client​

The constructor initializes the ColBERTv2 class instance and sets up the request parameters for interacting with the ColBERTv2 retrieval server. This server is hosted remotely at 'http://20.102.90.50:2017/wiki17_abstracts.

  • url (str): URL for ColBERTv2 server. Defaults to "http://0.0.0.0"
  • port (Union[str, int], Optional): Port endpoint for ColBERTv2 server. Defaults to None.
  • post_requests (bool, Optional): Flag for using HTTP POST requests. Defaults to False.

Example of the ColBERTv2 constructor:

class ColBERTv2:
    def __init__(
        self,
        url: str = "http://0.0.0.0",
        port: Optional[Union[str, int]] = None,
        post_requests: bool = False,
    ):

Under the Hood​

__call__(self, query: str, k: int = 10, simplify: bool = False) -> Union[list[str], list[dotdict]]​

Parameters:

  • query (str): Search query string used for retrieval sent to ColBERTv2 server.
  • k (int, optional): Number of passages to retrieve. Defaults to 10.
  • simplify (bool, optional): Flag for simplifying output to a list of strings. Defaults to False.

Returns:

  • Union[list[str], list[dotdict]]: Depending on simplify flag, either a list of strings representing the passage content (True) or a list of dotdict instances containing passage details (False).

Internally, the method handles the specifics of preparing the request query to the ColBERTv2 server and corresponding payload to obtain the response.

The function handles the retrieval of the top-k passages based on the provided query.

If post_requests is set, the method sends a query to the server via a POST request else via a GET request.

It then processes and returns the top-k passages from the response with the list of retrieved passages dependent on the simplify flag return condition above.

Sending Retrieval Requests via ColBERTv2 Client​

  1. Recommended Configure default RM using dspy.configure.

This allows you to define programs in DSPy and have DSPy internally conduct retrieval using dsp.retrieve on the query on the configured RM.

import dspy
import dsp

dspy.settings.configure(rm=colbertv2_wiki17_abstracts)
retrieval_response = dsp.retrieve("When was the first FIFA World Cup held?", k=5)

for result in retrieval_response:
    print("Text:", result, "\n")
  1. Generate responses using the client directly.
import dspy

retrieval_response = colbertv2_wiki17_abstracts('When was the first FIFA World Cup held?', k=5)

for result in retrieval_response:
    print("Text:", result['text'], "\n")

Written By: Arnav Singhvi